Graham is still calling for an investigation after Trump’s impeachment trial comes to a close, ideally by a nonpartisan actor akin to special counsel Robert S. Mueller III, he said.

“To my Democratic friends, I stood with you when you called for an outside entity to look into President Trump,” he said recently. “I’m asking you to allow somebody outside of politics to look at what happened with the Bidens.”

Sparring in interviews as impeachment hurtles toward almost-certain acquittal, Graham and Biden have both downplayed the impact on their personal relationship. Graham has maintained that he “loves” Biden — “one of the finest men I know,” he reiterated last month — but also doesn’t think he’s “beyond being looked at.” Biden, meanwhile, told a newspaper in Graham’s home state that he doesn’t know “what’s gotten into Lindsey” but also doesn’t “have any time to hold a grudge.”

Jill Biden’s comments Monday on CNN described a deeper rift, though. The network’s John Berman had brought up Graham, “whom I think you count as a friend,” he began.

“We did,” Jill Biden said. “Yes.”